Progress towards a vaccine against onchocerciasis

Progress towards a vaccine against onchocerciasis

TOVA has its origins in the river blindness (onchocerciasis) vaccine program of the Edna McConnell Clark Foundation (EMCF) that contributed $21.6 million between 1985 and 1999.

 

This investment focused on:

  • development of experimental animal models for screening candidate vaccine antigens
  • analysis of immunological mechanisms evoked by immunization with protective recombinant vaccine antigens
  • identification of protective antigens

When the programme ended, the work of African, American and European laboratories had developed three animal models, identified a portfolio of 15 O volvulus vaccine candidates including eight that were tested in the O ochengi bovine model, and obtained proof-of-principle of vaccination against infection ()Table 3).

The impetus given by EMCF was carried forward by the European Union through its Directorate-General for Research and Innovation (FP5, VARBO; FP6, SCOOTT; FP7, E PIAF, Enhanced Protective Immunity Against Filariasis, coordinated by Professor David W Taylor), and by the US NIH National Institute of Allergy and Infectious Diseases (The development of a recombinant vaccine against human onchocerciasis, headed by Dr Sara Lustigman).

The work of these programmes:

  • increased the understanding of the epidemiology and pathology of onchocerciasis
  • helped define the mechanisms of protective immunity against filarial parasites
  • demonstrated the role of parasite-induced immunomodulators in expression of protective immunity
  • identified three candidate vaccine antigens that have proven to be efficacious in three different filarial animal model systems and in five independent laboratories.
Table 1, Progress towards a vaccine against onchocerciasis (river blindness)